The subject matter disclosed herein relates to a key bar compression apparatus. Specifically, the subject matter disclosed herein relates to a key bar compression apparatus for reducing key bar vibration and associated noise in dynamoelectric machines.
A stator of a dynamoelectric machine, such as an electric power generator, generally includes a stator core and a stator frame. The stator core typically has a cylindrical shape and includes a stack of insulated steel laminations. Each lamination is a segment of a full circle that has slots on its inner diameter to accommodate a stator winding and dovetail slots on its outer diameter.
The stator frame has plurality of key bars connected thereto, each key bar having a dovetail to provide structural support for the stator core. During assembly of the stator core, each lamination is installed into the stator frame by engaging a dovetail slot of the lamination onto a corresponding key bar dovetail. Sufficient clearance is provided between the key bar dovetails and the faces of the lamination to allow for easy assembly of the stator core, while taking into consideration the location and dimensional tolerances of the key bar and laminations. The clearance between the three faces of the key bar dovetail and the opposing faces of the corresponding lamination dovetail slots varies randomly due to the random location of the key bar dovetail within its location tolerance along the length of the key bar. Due to this variable clearance, the actual contact locations between the key bar dovetail and the corresponding lamination (and hence the contact locations between the stator frame and the stator core) is randomly distributed.